Device for gluing a tail cant of a roll and product roll

ABSTRACT

A device for gluing a tail cant of a roll or log of wound web material, includes a support for the roll, a dispenser of glue, a movable blade on which a gluing application edge is provided, the blade ( 5 ) being oriented parallel to the roll-longitudinal axis (CD). The glue application edge ( 10 ) of the blade ( 5 ) has interrupted glue application surface.

TECHNICAL FIELD

In paper products wound to a roll or reel or log using tissue-paper ornon-woven material, being products as toilet papers or kitchen towelsthe trailing end or trailing cant of the roll or log is glued to anunderlying web of the roll or log. “Log” is a material web wound to areel in a rewinder, said log finally being cut into a plurality ofpart-lengths for final roll as toilet paper roll or kitchen towel roll.For using the first sheets of the roll the first sheet glued to anunderlying sheet has to be torn off.

BACKGROUND ART

From US 2005/0199761 A1 and US 2005/0199759 A1 it is known to controlthe strength and location of bonds by controlling the penetration ofadhesive into the tissue. This stands in connection with easy startingrolls of perforated tissue product which have a reduced tendency to plyseparate. Such rolls are formed with an adhesively secured doubled overtail tap folded against the roll.

A method or an apparatus for securing the tail or outer terminalconvolution of a toilet tissue cant or similar roll product to theconvolution immediately adjacent the tail is known from U.S. Pat. No.4,026,752. The tail of the roll product is secured by means of adhesive,and the method includes the step of ejecting a predetermined quantity ofadhesive directly onto the subjacent convolution of the roll productwhile the tail is unwound there from. The adhesive is distributed alongthe length of the cant at spaced apart locations adapted to underlie therewound tail, thereby allowing the tail to be adhesively secured to thecant. Each adhesive applicator module includes a plurality of dispensingnozzles operative to eject a measured quantity of adhesive onto a cantunderlying the same.

WO 95/15902 describes a device for gluing the tail end of a reel ofwound web material comprising a dispenser of glue for applying the glueto the reel and means for rewinding the tail end after the glue has beenapplied. Applied to the tail end is the glue by a transverse bar as acontinuous glue strip and upwardly the bar is provided with a concavesurface which is in practice a longitudinal channel extendingsubstantially along the whole length of the bar.

DISCLOSURE OF THE INVENTION

It is the problem (object) to be solved to reengineer the tail sealingprocess so that a soft tear off of paper could be secured withoutdisruptions of first and following plies, combined with improved opticalappearance.

This problem is solved by a device for gluing a tail cant or tail sheetof a roll or log of wound web material, inter alia, comprising a supportfor the roll or log, a dispenser of glue, at least one movable blade onwhich a glue-application-edge is provided, said blade being orientedparallel to the roll or log longitudinal axis (cross machinedirection—CD). The glue application edge of the blade has an interruptedglue application surface.

The device according to the invention may comprise at least one movableblade. Although using one movable blade is preferred, it is alsopossible that such a device may comprise two, three or even more ofthese movable blades.

By this solution it is possible for the consumer to avoid strugglingwith too sticky tail sealing. Furthermore, it is avoided that more thanone sheet is torn off and it is avoided to disrupt the ply lamination.This is achieved with low costs and pleasant optical appearance. Incontrast to the prior art not a continuous glue strip is applied but aglue strip with interruptions accordingly the product rolls are to behandled in a better manner and with better comfort.

Tail sealing of such paper product rolls or logs is necessary especiallyfor keeping the form of the roll in handling (conveying) of the rollsduring manufacture and for packaging the rolls. Thereafter tail sealingwould not be necessary. During conveying forces are applied to the rolland the tail sheet in cross machine direction CD, i.e. parallel to thelongitudinal axis of the roll. According to the teaching of the presentinvention sufficient tail sealing force against tearing off is achievedallowing simultaneously a simple and easy tearing off in machinedirection MD, i.e. perpendicular to the longitudinal axis of the rollwhen separating the tail sheet of the roll without destroying underlyingsheets.

Furthermore, the glue application edge of the blade is a lengthwisediscontinuous edge and preferably the glue application edge of the bladeprovides in longitudinal direction merlons and crenels, said merlonsforming the glue application surface.

There exist two possibilities for orientation of portions of the glueapplication surfaces. According to one possibility the portions of theglue application surfaces are lengthwise or spotlike oriented in CD ofthe roll or log i.e. parallel to the longitudinal axis of the roll. Inthe CD-orientation of the portions an excellent gluing effect keeps thesheet with safety on the roll or log when the roll or log is conveyed inCD direction and a relative movement between the roll or log and theconveying means creates a force applied to the tail sheet. Due to therow of portions of the glue application surface a smaller tear off forceis necessary for separating the tail sheet from the roll so that bothrequirements being normally in contradiction are fulfilled.

As a second possibility portions of the glue application surface arelengthwise oriented in a direction perpendicular to the roll or loglongitudinal axis (machine direction MD). Also with this possibility thetwo requirements are fulfilled in an optimised manner because in a rowthe larger length of the portions of the glue application surface(orientation in MD) also contributes to a higher gluing effect in CD anda more easy tearing off in MD is possibly without destroying theunderlying sheet, because tearing off starts with a lower amount ofglued areas because the glue portions on the tail sheet are extending inMD.

An essential point is the choice for the amount of glue applicationsurface being for instance between 25% and 90% of the surface glueapplication edge of the blade, preferably between 30% and 70% and mostpreferably between 50% and 60%.

According to a further possibility the glue application surface of theblade is formed by portions of the blade being oriented lengthwisesubstantially perpendicular to the longitudinal extension of the bladeand extend beyond the widths of the blade. By such a blade portions ofthe glue application surface are lengthwise oriented in a directionperpendicular to the roll or log longitudinal axis (MD).

On the one hand, the portions forming the glue application surface areintegral parts of the blade or, on the other hand, the portions formingthe glue application surface are parts fastened in a distanced manner tothe blade.

By such a solution it is possible to keep the widths of the blade itselfsmall and thin.

Furthermore, the problem is solved by a product roll of tissue-paper ornon-woven material comprising a web formed of paper sheets connected oneto another by weakened lines and wound to the product roll, a tail sheetbeing glued to underlying sheet or sheets. A glue pattern is present inform of a row of separated glue portions. Preferably the ratio betweenlength and width of the respective glue portions is at least 2:1,especially at least 3:1.

Preferably, the longitudinal extension of the glue portions is parallelto the longitudinal axis of the roll or the longitudinal extension ofthe glue portions is perpendicular to the longitudinal axis of the roll.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic perspective view of a device for tail sealingof a roll by applying glue.

FIGS. 2 a,b is a diagrammatic view of a blade having a discontinuousglue application edge.

FIG. 3 a shows a roll with portions of a glue pattern oriented in MD.

FIG. 3 b shows portions of a glue pattern being oriented in CD.

FIGS. 4 a to 4 f show another embodiment of a tail sealing deviceillustrating stepwise the tail sealing process.

FIGS. 5 to 12 show different embodiments of the blade.

EMBODIMENTS OF THE INVENTION

FIG. 1 illustrates in a diagrammatic manner a roll or log 1 conveyed indirection of the arrow 2 on a conveying surface 3. Beneath a glueapplication slot 4 (not illustrated in FIG. 4) a blade 5 and gluechamber 6 (not illustrated here) are provided for application glue onthe tail sheet 7 on the roll 1. The blade 5 is movable forward andbackwards according to an arrow 8.

When a log from which shorter lengths of rolls are cut is leaving therewinder head it rolls down a slope where a blade is placed in CD. Theglue application surface of the blade carriers aforementioned glue andtransfers it to the end of the roll (tail sheet) whilst continuing therevolution of the log down the slope, the glue carrying paper is wrappedfurther around the log and a tail sheet is attached to the log.Alternatively, spray application, moving spray head in CD or anycontinuous means like a wire in CD can provide the same result.

The longitudinal axis of the roll 1 is marked in FIG. 1 as having thereference letter a.

The glue application blade illustrated diagrammatically in FIG. 2 a hasa glue application edge 10 having a glue application surface formed inits entirety by surface portions 11 a being crenels interrupted bymerlons 12. The portions 11 a are lengthwise oriented in CD and have alength l₁ and the merlons 12 have a length l₂. The blade itself has awidth w₁.

FIG. 2 b shows an alternative or embodiment of the blade 5. There areglue application portions 11 b. These are oriented in MD. These portionshave a length l₃ and are in CD in a distance of d and a width w₂.

According to the blade illustrated in FIG. 2 a the portions 11 a of theglue application surface is oriented in CD and the portions 11 baccording to FIG. 2 b are oriented in MD, which leads to a glueapplication pattern result illustrated in FIG. 3 a and FIG. 3 b.

In FIGS. 4 a to 4 f another mode of glue application and tail sealing isillustrated step by step from FIG. 4 a to FIG. 4 f. This device shows anupper conveyer belt 13 as an endless belt and a lower conveyer belt 14as an endless belt. Between these conveyer belts a roll 1 is conveyed inthe direction of the arrow 15, since the conveyer belts are driven inthe same direction. The tail or tail sheet 7 is sucked into the gap 4and the blade 5 is retracted within the glue chamber 6. Downstream ofthe gap 4 a stationary support 3 is illustrated, wherein a pressureroller 16 is provided. This condition is illustrated in FIG. 4 a. In thenext step according to FIG. 4 b the blade 5 is extended in an upperposition and glue is applied here not to the tail sheet but on thecircumference of the roll 1 where the tail sheet ends. Thereafter, theblade 5 is retracted and the roll 1 is furthermore transferred to theright side on the support 3. This is illustrated in FIG. 4 c. In FIG. 4d a position is illustrated where the roll 1 is provided between theupper conveyer belt 13 and the pressure roller 16, which is then rotatedsuch that the roll 1 is rotated between the conveyer belt 13 and thepressure roller 16. This is illustrated in FIGS. 4 d and 4 e. In FIG. 4e is visible the tail sheet already fastened by gluing and by thepressure roller the bonding effect is increased. Then the rotation ofthe pressure roller is stopped and the roll 1 is delivered in thedirection of the arrow 17. In FIG. 4 e the applied glue pattern ismarked by the reference number G.

Tests were made with some of several tail seal blades 1 to 8 accordingto FIG. 5 a to FIG. 12 b (8 different blades), whereby blades 1, 2, 4, 5and 7 are blades according to the invention and blades 3, 6 and 8 areblades according to the prior art shown for comparative reasons.

FIG. 5 a shows the whole blade and FIG. 5 b an enlarged part of theblade 1 with the contour of the glue application edge. The thickness w1of the blade is 2.1 mm the merlon 11 has a length l₁ of 10 mm and thecrenel 12 a length l₂ of 5 mm. The glue application area, which meansthe sum of all portions of the glue application surface, is 66% of thewhole glue application edge when the glue application edge is notinterrupted or discontinuous.

Tail seal blade 2 is illustrated in FIGS. 6 a, 6 b, 6 c and 6 d. TheFIGS. 6 b and 6 d show the glue application surface having a groove sothat the glue application surface is reduced. This is a possibilitybeing not considered in connection with the tests. The glue applicationarea here is 50% and the thickness w₁ is also 2.1 mm. The length l₁ isthe same as the length l₂ being 5 mm.

Tail seal blade 3 is illustrated in FIG. 7 a and FIG. 7 b. Here the glueapplication area is 100% and the thickness w₁ 2.1 mm. This blade is usedfor comparison only, because this complies with the prior art.

By the blades 1 and 2 a glue pattern according to FIG. 3 b is achieved.

Tail seal blade 4 as illustrated in FIGS. 8 a and 8 b uses inserts 11 bas illustrated in FIG. 2 b. The same is for tail seal blade 5illustrated in FIGS. 9 a and 9 b. The glue application area is 66%. Thethickness w₂ is 2 mm and the width l₃ 10 mm. The distance between theinserts 11 b(d) is 15 mm.

Tail seal blade 5 according to FIGS. 9 a and 9 b has a glue applicationarea of 33%. The thickness w₂ is 2 mm and the widths l₃ is 10 mm. Thedistance d between the inserts 11 b is 30 mm.

Again tail seal blade 6 according to FIGS. 10 a and 10 b shows a blade 5according to the prior art without discontinuous glue applicationsurface. Therefore, the glue application area is 100% and the thicknessw₁ is 2.1 mm.

Tail seal blade 7 shows another crenellated configuration of the glueapplication edge, where the crenels 12 have the same lengths l₂ of 20mm. The lengths l₁ of the merlons 11 is different being 10 mm and 40 mm.Correspondingly, the glue application area is 50% and the thickness ofthe blade is 2.1 mm.

Finally, tail seal blade 8 shows a blade according to the prior artwithout discontinuous glue application edge. Therefore, the glueapplication area is 100% but the thickness w 1 now is 2.8 mm. This sealblade 8 is illustrated in FIGS. 12 a and 12 b.

The blades were tested with different glues according to the followingtable 1.

Variant Blade Glue Solid Content Color 1 8 STC 0190 (Henkel) ? — 2 4 TS0190 (Henkel) 6 — 3 5 TS 0190 (Henkel) 6 — 4 7 TS 0190 (Henkel) 6 —

The test results are listed in table 2 as an evaluation matrix.

A) Tear off B) Tear off C) Penetration D) Optical E) Adhesion F)Penetration G) Optical behaviour behaviour behaviour through appearanceto ply behaviour to ply appearance Variant MD CD top ply TS TSunderneath underneath AP AP 1 5 1 4 4 5 5 4 2 1.5 2 3 1 1.5 1.5 1 3 12.5 3 1 1 1 1 4 1.5 2 3 1.5 1 1 1

Tables 1 and 2 illustrate the variants 1 to 4.

As follows, the basis for evaluation and weighting is as follows:

Adhesion at Tail Seal Point

-   -   A) Tear off behaviour MD:        -   1=soft/5=strong    -   B) Tear off behaviour CD:        -   1=strong/5=soft    -   C) Penetration behaviour through top ply:        -   1=low/5=high    -   D) Optical appearance:        -   1=good/5=bad

Adhesion at Application Point

-   -   E) Adhesion to ply underneath:        -   1=soft/5=strong    -   F) Penetration behaviour to ply underneath:        -   1=low/5=high    -   G) Optical appearance:        -   1=good/5=bad

Table 2 demonstrates that those variants 2, 3 and 4 according to theinvention (using blades 4, 5 and 7) result in an improved productperformance in terms of optical appearance, adhesion and penetrationcompared with variant 1 according to the prior art (using blade 8). Inaddition product-rolls obtained from variants 2, 3 and 4 arecharacterized by an improved tear-off strength in CD than in MD comparedto product-rolls according to the prior art (variant 1) thereby leadingto a very convenient product for the consumer in view of tearing off thefirst sheet.

Table 3 shows the weighting factor with respect to the consumers and theproduction.

Consumer Production Tear off MD TS 25% 75% Tear off CD TS 75% 25%Penetration TS 25% 75% Optical App. TS 25% 75% Adhesion AP 75% 25%Penetration AP 75% 25% Optical App. Ap 75% 25%

1-17. (canceled)
 18. Device for gluing a tail cant or tail sheet of aroll or log of wound web material, comprising a support for the roll orlog, a dispenser of glue, at least one movable blade on which a gluingapplication edge is provided, said blade being oriented parallel to theroll or log longitudinal axis, wherein the glue application edge of theblade has an interrupted glue application surface.
 19. The deviceaccording to claim 18, wherein the glue application edge of the blade isa lengthwise discontinuous edge.
 20. The device according to claim 19,wherein the glue application edge of the blade provides in longitudinaldirection merlons and crenels, said merlons forming the glue applicationsurface.
 21. The device according to claim 18, wherein portions of theglue application surface are spots oriented in a cross machine directionof the roll or log.
 22. The device according to claim 18, whereinportions of the glue application surface are lengthwise oriented in across machine direction of the roll or log.
 23. The device according toclaim 18, wherein portions of the glue application surface arelengthwise oriented in a direction perpendicular to the roll or loglongitudinal axis.
 24. The device according to claim 18, wherein theglue application surface is between 25% and 90% of the glue applicationedge of the blade.
 25. The device according to claim 24, wherein theglue application surface is between 30% and 70% of the glue applicationedge of the blade.
 26. The device according to claim 24, wherein theglue application surface is between 50% and 60% of the glue applicationedge of the blade.
 27. The device according to claim 23, wherein theglue application surface of the blade is formed by parts being orientedlengthwise substantially perpendicularly to the longitudinal extensionof the blade and extend beyond the widths (w 1) of the blade.
 28. Thedevice according to claim 27, wherein the parts are integral with theblade.
 29. The device according to claim 27, wherein the parts arefastened to the blade in a distanced manner.
 30. Product-roll oftissue-paper or non-woven material, comprising a web formed of papersheets connected one to another in a row by weakened lines and wound tothe product roll, a tail sheet being glued to underlying sheet orsheets, wherein a glue pattern is present in the form of a row ofseparated glue portions.
 31. The product-roll according to claim 30,wherein the longitudinal extension of the glue portions is parallel tothe longitudinal axis of the roll.
 32. The product-roll according toclaim 30, wherein the longitudinal extension of the glue portions isperpendicular to the longitudinal axis of the roll.
 33. The product-rollaccording to claim 30, wherein the ratio between length and width of therespective glue portions is at least 2:1.
 34. The product-roll accordingto claim 33, wherein the ratio between length and width of therespective glue portion is at least 3:1.